The present invention relates to a method of carrying out a chemical reaction, in particular a fluorination reaction between at least two fluids.
A constant aim in the chemical industry and chemistry generally is to improve control over chemical reactions. Greater control over reactions may lead to, for example, improvements in safety, increases in the reaction product yield and/or purity, or the isolation of valuable highly reactive intermediate products. In particular, greater control over reagent mixing, fluid flow, heat sinking/sourcing and catalytic efficiency is desirable. A general method which provides such improved control over reactions would therefore be advantageous.
According to the present invention there is provided a method of carrying out a fluorination reaction between at least two fluids, one of the at least two fluids comprising a compound to be fluorinated and another of the at least two fluids comprising a fluorinating agent, the method comprising providing respective flow paths for the at least two fluids, said flow paths communicating with each other in a region in which the at least two fluids may contact each other, and flowing the at least two fluids along said flow paths such that in said region the at least two fluids contact each other and a chemical reaction occurs between them, said region having a width perpendicular to the direction of flow in the range 10-10,000 micrometers.
It has been found that using a so-called xe2x80x9cmicroreactorxe2x80x9d, that is a reactor having dimensions perpendicular to the flow direction of less than 10,000 micrometers, according to the present method, improved control over a fluid chemical reaction can be achieved, which can result in significant improvements in reaction product yield and/or purity, as well as other benefits.
The reaction region may have a width (defined as perpendicular to the direction of flow) in the range 10-10,000 micrometers. Preferably, the reaction region has a width in the range 10-500 micrometers. Most preferably, the reaction region has a width in the range 10-200 micrometers.
The length of the reaction region (measured in the direction of the flow) is typically in the range 10 micrometer to 1 meter. The optimum length will be determined by the kinetics of the reaction to be carried out and the flow rates to be employed. For example, a reaction having slow kinetics would require a longer reactor length than a reaction with faster kinetics for the same flow rate.
Typically, the microreactor used in the present method is the same general type of apparatus as disclosed in patent applications WO 96/12541 and WO 96/12540, and the teaching of those documents is incorporated herein by reference. Input and output ports for reactants and products respectively may be arranged to suit the particular reaction being carried out. Examples of different microreactor configurations are shown in FIGS. 1 to 5.
Whereas the apparatus as described in WO 96/12541 and WO 96/12540 is formed from silicon or glass, the microreactor used in the present invention may be produced in a number of materials using standard processing techniques. For example, in fluorination reactions, the microreactor may be formed from nickel, copper or zirconium or another suitable material non-reactive with fluorine. Polymer materials may be used to form the microreactor for some reactions.
An advantage of the method of the present invention is that reactions may be readily scaled up from laboratory scale to operating plant scale. The reaction conditions are identical and the technology is immediately transferable.